Absorption refrigeration circuit components are connected using pipe conduits. The pipe conduits and components are welded or brazed together.
However, welding and brazing are labor-intensive, and accordingly not suited to mass production.
Inasmuch, a coupling structure incorporating a metal gasket is known as a method suited to mass production, as disclosed in JP 04-60280 A.
FIGS. 9 and 10 hereof show, respectively, a gasket used in the coupling structure disclosed in JP 04-60280 A, and the coupling structure.
As shown in FIG. 9, a metal gasket 100 comprises an annular base part 101, grooves 102, 102 formed in upper and lower surfaces of the base part 101, and sealing members 103, 103 fitted into the grooves 102, 102.
As shown in FIG. 10, blade parts 106, 107 are formed respectively on upper and lower flanges 104, 105. When a nut 111 is threaded onto a bolt 109, the blade parts 106, 107 engage with the sealing member 103.
In this type of coupling structure the blade parts 106, 107 must be provided to the upper and lower flanges 104, 105. Flanges 104, 105 that are provided with such blade parts 106, 107 are expensive, and using a coupling structure of this type increases the associated manufacturing costs.